The Electrocatalytic Oxidation Of D-Glucose Based On Nanoporous Gold Film

Glucose is widely used in modern life and industry as a nontoxic, inexpensive and renewable resource. Since Rao and Drake first reported the glucose oxidation on platinized-Pt electrodes in phosphate buffer solution in the 1960s, electrocatalytic oxidation of glucose has been extensively investigated as a key reaction in the fields of sensors and fuel cells, etc. Exploiting electrocatalyst with high activity for glucose oxidation is central importance in practical applications. In this paper, nanoporous gold (NPG) and Pt-NPG, Pd-NPG catalysts were prepared. The high surface-to-volume ratio and great porosity of these catalysts were proposed as active electrodes for glucose electrooxidation in neutral and alkaline solutions. The structure and surface properties of catalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), cyclic voltammetry (CV), and amperometric measurement. The main contents are summarized as follows:(1) Nanoporous gold (NPG) samples with different ligament size were prepared via selective dissolution (dealloying) of Ag from 12-carat white gold leaves (Au/Ag alloy,100 nm thickness). Comparing to bulk and polycyrstalline gold electrodes, NPG electrode exhibits a high catalytic activity towards glucose electrochemical oxidation and the anodic currents occurred at considerably negative potential both in neutral and alkaline solutions. Furthermore, glucose detection was studied in 0.1 M pH 7.4 phosphate buffer saline (PBS) media under the nonenzymatic electrochemical condition. The results showed an improved performance to the glucose detection and a linear range up to 20 mM with a detection limit down to 1μM at a signal-to-noise ratio of 3 and fast response time. This work indicated a potential to develop novel enzyme-free glucose sensors for practical applications.(2) It is well-known that Pt and Pt-based alloys are the most important anode catalysts in fuel cells. We reported a type of Pt-Au bimetallic membrane electrocatalysts constructed by depositing an atomically thin layer of Pt onto the entire surfaces of nanoporous gold (NPG), named Pt-decorated NPG (Pt-NPG). These structures showed superior activity toward a series of important electrochemical reaction including methanol oxidation, Formic acid oxidation, thus are regarded as promising electrocatalysts in proton exchange membrane fuel cells. Here, we focus on their electrocatalytic properties toward glucose oxidation in view of exploiting their potential as novel bimetallic electrocatalysts for glucose fuel cell.Furthermore, using the same method, Pd-Au bimetallic membrane catalysts with different Pd compositions were obtained and their electrocatalytic performances for glucose were tested.